Pre-shaped break point convolute for a pressurized suit

ABSTRACT

A TWO-CONVOLUTE SYSTEM INCLUDES A CENTRAL ROOT WHICH HAS A MUCH SMALLER NATURAL DIAMETER THAN THE TWO OUTER ROOTS, SO THAT WHEN THE CONVOLUTE IS PRESSURIZED, IT STILL MAINTAINS A WELL DEFINED BREAK POINT. PATTERNS FOR THE CONVOLUTE SECTIONS ARE DISCLOSED.

Ont. 26, 1971 D. E. GETCHELL 3,514,783

PRE-SHAPED BREAK POINT CONVOLUTE FOR A PRESSURIZED SUIT Filed Dec. 2o. 1968 2 shams-sheet 1 wwf/arm? y a if ,ff afa/ya@ Oct. 26, 1971 D. E. GETCHELL 3,614,738

PRE-SHAPED BREAK POINT CONVOLUTE FOR A PRESSURIZED SUIT Filed Dec. 20, 1968 2 Sheets-Sheet 2 J j; w)

lij Patented Uct. 26, 197i 3,614,788 PRE-SHAPED BREAK POIINT CONVOLUTE FOR A PRESSUREZED SUIT Douglas E. Getehell, Windsor Locks, Conn., assignor to United Aircraft Corporation, East Hartford, Conn. Filed Dec. 20, 1968, Ser. No. 785,603 Int. Cl. A62b 17/00 US. Cl. 22.1 1 Claim ABSTRACT OF THE DISCLOSURE A two-convolute system includes a central root which has a much smaller natural diameter than the two outer roots, so that when the convolute is pressurized, it still maintains a well defined break point. Patterns for the convolute sections are disclosed.

BACKGROUND OF THE INVENTION Field of invention This invention relates to pressurized suits, and more particularly to a pre-shaped convolute assembly therefor.

Description of the prior art It is well known in the art of pressurized suits to provide convolutes which tend to resist stiffness as a result of pressurization of the suit. In fact, the primary purpose of the convolute is to provide break points in the otherwise stiff cloth so as to permit flexing of joints. In some instances, such as an ankle joined to the top of a boot, it has been found that only a single, well-defined break point is necessary to do the job. However, convolutes known to the prior art require a large number of convolutes in order to avoid breaking outwardly, into a substantially cylindrical shape, as a result of pressure within the convolute assembly. When a large number of convolutes are employed, the root of each convolute tends to stabilize the root of each adjacent convolute. However, when only two convolutes are used, thus to provide but a single break point, there is a tendency on the part of the single root to expand outwardly as a result of the great force applied thereto from the pressure within the suit. This expansion of the central root causes the break point of the root to virtually disappear. As a result, convolute assemblies having but two convolute sections do not provide the required breaking capability, and thus require far too much torque for flexion resulting in a severe limitation on mobility and fatigue of the wearer.

SUMMARY OF INVENTION The object of the present invention is to provide a small number of convolutes having at least. one well defined break point when under pressure.

According to the present invention, a convolute assembly having a small number of convolutes therein is provided with at least one well defined break point by having at least one inner root diameter smaller than the end root diameters.

The convolute system in accordance with the present invention provides a well defined break point in a convolute assembly having only two or a few convolutes therein. The invention may also be used in convolute assemblies having more convolutes, though it becomes more and more unnecessary as the number of convolutes increases.

The foregoing and other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of a preferred embodiment thereof, as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a simplified side elevation of a two-convolute assembly known to the prior art;

FIG. 2 is a side elevation of a prior art convolute assembly illustrated when under pressure without restraint;

FIG. 3 is a side elevation of the prior art convolute illustrated with a dorsal restraint while under pressure;

FIG. 4 is a side elevation, partially broken away, of an unpressurized convolute assembly in accordance with the present invention;

FIG. 5 is a side elevation of the convolute assembly illustrated in FIG. 4, shown without restraint while under pressure;

FIG. 6 is a side elevation of the convolute assembly of FIG. 4 shown with dorsal restraint while under pressure;

FIG. 7 is a plan view of a pattern for forming an inner convolute half in accordance with the present invention;

FIG. 8 is a plan view of a pattern for fabricating an outer convolute half in accordance with the present invention; and

FIG. 9 is a side elevation of an alternative exemplary utilization of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The convolute section shown in FIGS. 1-3 is comprised of two sections joined together at an inner root 10 by the sewing together of an inner half convolute 12 with another inner half convolute 14. The inner half convolutes 12, 14 are each sewn to outer half convolutes 16, 18 which arein turn sewn to substantially cylindrical (or otherwisesuitably shaped) sections 20, 22. The purpose of such a convolute section is to provide a clearly defined break point between the sections 20, 22 so as to permit iieXing of the joint. For instance, the section 22 may comprise the top of a boot, and the section -20 may comprise the lower leg; the convolute section should provide a clearly defined break point to permit forwardly fiexing the foot, as in walking.

Referring now to FIG. l, the convolute section, while not under pressure, appears as it should, with a well delined break point at the inner root 10 which separates the two convolute sections from each other. However, once pressurized, the convolute section will assume a shape substantially as shown in FIG. 2. It can be seen in FIG. 2 that the pressure applied to the convolute tends to cause the inner root 10 to grow substantially, which eliminates the well defined break point, and. thereby spoils the convolute for its intended purpose. A similar result is achieved as illustrated in FIG. 3 when restraints 28 are utilized on each side of the convolute to keep the overall convolute assembly from growing. Even though the section in line with the restraint tends to resist growth and will have an overall length the same as the unpressurized convolute assembly illustrated in FIG. l, there is growth at the right and the left sides with respect to the restraint.

In accordance with the present invention, it has been found that if the convolute apparatus of the type shown in FIG. l is modified so as to be, in a sense, pre-distorted, then it will maintain a well defined break point even when pressurized. Referring to FIG. 4, :a convolute assembly in accordance with the present invention is illustrated in the unpressurized condition. Therein, the inner root 10a is of a substantially smaller diameter than the two outer roots 24a, 26a. As a result, when the convolute assembly is pressurized as illustrated in FIG. 5, the inner root 10a assumes a diameter substantially equal to the outer roots 24a, 26a. Thus a well defined break point is preserved.

Even when the convolute assembly is restrained by plug load restraints 23 as illustrated in FIG. 6, the inner root 10a maintains a diameter nearly equal to that of the outer roots 24a, 26a, and the well delined break point is preserved.

lPatterns for making a convolute system in accordance with the present invention are illustrated in FI'GS. 7 and 8. In FIG. 7, a pattern 30 is illustrated which may be used for making the inner convolute halves 12a, 14a. In IFIG. 8, a pattern 32 is illustrated which may be utilized to form the outer convolute halves 16a, 18a. Notice that the diameter of the pattern 30 is less than the diameter of the pattern 32, and the pattern 30 is caused to make a much flatter truncated cone by having only a .small sector 34 removed therefrom, whereas a sector 35 in the pattern 32 is much larger and thus causes a steeper cone of a greater diameter to be fashioned from the pattern 32. This conforms with the structure illustrated in FIGS. 4-6 and described hereinbefore.

Thus the present invention permits the utilization of but a single inner break point, in a convolute assembly having but two convolutes, or perhaps only a few convolutes, without loss of the break point while under pressure. This permits a high degree of flexibility, even in the case Where plug load restraint is provided to limit the growth of the convolute assembly when pressurized.

An alternative embodiment of the invention is illustrated in FIG. 9 wherein a convolute section 3'6 is tapered. As is known, a tapered section, when rigid as a result of internal pressure, acts much like a tapered steel beam in its exure characteristics. Thus, the tapered section 36 tends to bend or break at convolutes having small diameters rather than at convolutes having larger diameters. By employing a small root modified convolute of the present invention, one root 38 can be made to have a suiciently small diameter so that it tends to break more readily than any remaining roots 40. This makes it possible to utilize a tapered convolute when otherwise one is of no use.

In a similar fashion, convolute sections similar to the section 36 may be provided with small roots at each end so as to tend to stabilize the convolute section (as described with respect to FIGS. 4 through 6 hereinbefore), whether the section be tapered or substantially cylindrical. In other Words, the present invention may be employed wherever a substantial break point is desired in a pressurized convolute section.

Although the invention has been shown and described with respect to a preferred embodiment thereof, it should be obvious to those skilled in the art that the foregoing and various other changes and omissions in the form and detail thereof may be made therein without departing from the spirit and the scope of the invention.

Having thus described a typical embodiment of my invention, that which I claim as new and desire to secure by Letters Patent of the United States is:

1. In a pressurized suit, a restraint cloth convolute assembly comprising:

a plurality of cloth frusto cones, each of said frusto cones having a large diameter opening and a small diameter opening, the large diameter opening of each of said frusto cones having substantially the same diameter, rrst and second ones of said frusto cones positioned at respective opposite ends of said convolute assembly having their small diameter ends oriented away from the longitudinal center of said convolute assembly, said iirst and second frusto cones having small diameter openings of a given diameter, and a plurality of third ones of said frusto cones, each having a small diameter opening of a diameter less than the diameter of the small diameter opening of said iirst and second frusto cones, two of said plurality of third frusto cones being joined at their large diameter edges to respective ones of said first and second frusto cones and at least a pair of said plurality of third frusto cones being joined together at their small diameter edges forming a convolute section having at least one inner convolute root which as an unpressurized diameter substantially less than the diameter of the roots at the respective ends of said section.

References Cited UNITED STATES PATENTS 1,165,449 l2/l915 Rietz 13S-12.1 X 1,795,266 3/1931 Smith 285-226 X 2,335,475 ll/l943 Beall 2-2.1 UX 2,967,305 1/1961 White et al. 2-2.1

PATRICK D. LAWSON, Primary Examiner G. H. KRIZMANICH, Assistant Examiner U.S. Cl. X.R. 285-226 

